i had this keychain for a long time and i thought u could make a launcher out of it but how, well this is the answer. u could probly make a keychain bb gun if u just takeout the ink tube thingymajig and put in a bb.

this instructable is amazin i have made it and it dosnt even take that long i have made a little change 2 it though and added a fork shaped wire 2 hold the string then when u fire the string just slips of bit by bit =]